Engine swap: 350 for a 454

I have 3/4 ton 87 suburban rear wheel drive with a 454. thinking of swapping engine with a 350. I would probably have to chang the PCM, and linkage, and exhaust. Can't think of a reason not to do it . Any one else done this. I was hoping to get better gas mileage and have a newer engine. (165000 on the old engine.) Any reason that it won't work?

You can swap any engine you want, It all comes down to your ability and skill to perform the swap. I'm not familiar with older engine, but If you were comparing the 5.7 to the 8.1 gas mileage is single digit with the 8.1, that's why I didn't get it.